It was with great amusement that I read Rihanna's latest River Island clothing line was designed with her own "fat days" in mind. Hahahahahahaha! Only she (at a size 6) would consider a collection that includes hot pants and fishnets "fat day" wear. (Oh to be 20-something with a body like hers!) But it did get me thinking about how universal that feeling is. No matter what size you are, or what kind of shape you're in, some days you feel pretty and slim and others ... not so much.

You know what "fat days" are, I'm sure ... those days when you feel extra frumpy and unlovely and bloated, whether it's because it's that special time of the month, or you've missed the gym (like say for the last four months), or you just overdid it all weekend. Lately, I've been feeling that way more days than not. But there are ways to pull yourself out of a fat-day slump. Here are my tricks and tips.

1. Don't go for the sweats. Repeat: STEP AWAY FROM THE SWEATS.

It's tempting to pull on your favorite stretched-out yoga pants or sweats, topped off with a baggy T-shirt, but choosing something a little more tailored will actually make you feel and look better! A soft and flowy yet fitted button-down like this polka-dot shirt from Lauren Ralph Lauren above will help you feel put-together without being too constricting, and you can pair it with a comfy pair of jeans or even walking shorts. I also recommend going for a pair of wedges or heels, if you own them! Side note: my instinct is to doubt this model ever has fat days, but who knows? Maybe hers are worse than mine! ($69.50 at lordandtaylor.com.)

Another good option is a tunic with some shape to it (i.e., with a few buttons rather than just a long billowy T-shirt) and some good, supportive leggings. You do own some good, supportive leggings, right? The kind that make you feel nice and compact, not like you're walking around in tights? This Coldwater Creek tunic top would do the trick. (50 percent off $37.99 at coldwatercreek.com.)

2. Do your hair and makeup.

My instinct on those extra sloppy days is to just say TO HELL WITH IT and barely even wash my face. I head directly for the ponytail holder and call it quits. BUT a much better approach, and one that works for me when I can get up the oomph to do it, is to take a little extra time for primping. Haul out the blow dryer or flat iron or (fill in hairstyling tool of choice) and "do" your hair. Then put on some makeup if you wear it. If you don't, I say try a little mascara and blush anyway! Pretend like you have a special occasion to attend. You do, actually -- it's your life!

3. Get a little exercise. Even just a TEENY BIT.

Go for a short walk, find some yoga videos on YouTube, go up and down your stairs a bunch of times, do some jumping jacks, have a dance party with your kids! Whatever it takes to get the blood flowing and a little flush to your cheeks -- and remind yourself that your body is truly a wonderland (John Mayer agrees). Whatever small amount of exercise you can do, it will help you feel better from the inside out. Honest!